1. Field of the Invention
The present invention relates generally to the field of optical detection and imaging of circulatory flow in biological tissues for research purposes; more specifically, this invention provides a method and apparatus for optical detection and video display of regional circulatory flow in an animal or plant organ perfused with a suspension of fluorescent or colored microspheres. The invention also encompasses an automated method and apparatus for calculating regional circulatory flow in biological tissues.
2. Prior Art
Radioactive microspheres are conventionally used for detecting and measuring circulatory flow in the organs of laboratory research animals and plants. Such information can reveal, for example, regions of restricted blood flow in heart and other animal organs. Microspheres of appropriate diameter are injected into the circulation of live test animals (or plants) and lodge in regions where the diameter of the circulatory system is smaller than that of the microsphere. The animal is then sacrificed and the tissue or organ of interest is carefully dissected into small volume elements. The resolution of the method can not exceed the number of the volume elements so either the method has low spatial resolution or the tissue must be dissected into many volume elements. Each tissue volume element is then individually weighed and processed, which conventionally involves extracting and filtering or ashing, adding solutions and counting the radioactivity with a scintillation counter. An alternative method employs colored microspheres, uses the same sample preparation steps, and determines color intensity from each volume element with a spectrophotometer. These current practices are labor intensive (extensive handling and keeping track of numerous tissue volume elements), require costly supplies and reagents, and produce radioactive samples and radioactive animal carcasses; furthermore, selection of the tissue volume elements must be done before analysis, can be done only once, and yields low spatial resolution of microsphere location.
3. Invention Disclosure
A written disclosure of this invention was submitted pursuant to the Invention Disclosure Program on Dec. 28, 1992, Disclosure Ser. No. 322511.
4. Government Support
This invention was made with government support, grant HL 50898, awarded by the National Institutes of Health. The government has certain rights in the invention.